The present invention relates generally to the field of plastic pipe working machines, and more particularly, is directed to a pipe transporting device that is capable of transversely moving previously cut lengths of plastic pipe through preheating and bell forming stations for delivery to a finished pipe exit station.
Pipe belling machines of the type contemplated by the present invention have in the past included a frame having a plurality of chain conveyors which function transversely of the frame in unison to carry previously cut lengths of plastic pipe across the frame toward a belling station.
The usual chain conveying systems have included spaced pluralities of pins which function to push successive lengths of pipe upwardly along a slightly inclined path toward the belling station. Usually, a plurality of transversely positioned moving belts have been associated with the chain conveyors, which belts are arranged for continuous operation during all periods when the machine is in use. The previously cut lengths of plastic pipe rest upon the moving belts as the pipes are indexed across the machine by the conveyors so that the belts function to rotate each length of pipe continuously as the pipe is conveyed transversely across the machine by the chain conveyors. The spaced pins on the chain conveyors have been provided to maintain the pipes in previously preset locations transversely along the frame as the pipes are being processed through the machine.
Most of the prior art belling machines of the type contemplated by the present invention comprise a plurality of discrete stations, the first one of which can be considered the receiving station to receive individual lengths of pipe from an extruder after the individual pipe is cut to a desired length by a known type of cutting saw. Transversely adjacent to the receiving station is positioned one or more heating stations wherein one pipe end can be indexed in a rotational manner beneath one or more infra-red heaters in a usual manner to permit one end of the pipe to be continuously heated as the pipe is transversely indexed across the machine by the chain conveyors and as the pipe is rotated by a moving belt.
A final station, the belling station, is positioned transversely adjacent to the heater or heaters wherein a power operated mandril is employed to press a predetermined shape onto the previously heated end of each length of pipe. The shape impressed upon the heated end of the pipe can be of any desired configuration in accordance with the design of the pipe by controlling the configuration and design of the shaping mandril and jaws. Suitable controls in the nature of limit switches, micro-switches and the like have been provided to control automatically the function of the chain conveyors, the power mandril and the time and operation of the belling cycle.
Pipe transporting machines of the general type contemplated by the present invention have usually been employed in conjunction with a belling mandril wherein the mandril can be designed to not only provide a bell or hub shaped end, but also, to simultaneously impress a radially inwardly facing groove in the hub end for receiving therein a sealing gasket to facilitate the easy assembly of a leak-proof joint when adjacent lengths of pipe are associated in end-to-end juxtaposition in well known manner.